1. Field of the Invention
The invention relates to a dual mode mobile terminal operating in a communication system having a wireless wide area network and a wireless local area network and, more particularly, to a method for adjusting a coverage of the wireless local area network.
2. Description of the Prior Art
In recent years, new communication technologies are developed and customers can select different kinds of personal communication systems to use voice/data services. The communication systems are, for example, GSM/WCDMA/CDMA2000 wireless wide area networks (WWAN) and voice service over wireless local area networks (WLAN).
Fixed Mobile Convergence (FMC) is developed by integrating a WWAN, a WLAN and a control center into a communication system. A FMC mobile terminal can be switched between WWAN and WLAN according to the signal levels transmitted by the WWAN and the WLAN. Normally. Because the fee of WWAN is high, the user would prefer to use the service of WLAN, especially when using a roaming service in different countries with different operators. When the mobile terminal connects the WLAN, the user may pay less fee than using the WWAN. However, the coverage of the WLAN is smaller than the WWAN's. When the mobile terminal passes through the boundary of the coverage of WLAN, the mobile terminal may switches from WLAN to WWAN. If the user frequently stays in the boundary, the mobile terminal may be forced to switch to WWAN and the user should pay much money even the WLAN can provide communication services.
In another hand, the voice quality of the WLAN is not good as the voice quality of the WWAN because of network delays. Some user prefers communicates within WWAN because of the voice quality. The user may be want to reduce the coverage of the WLAN.
In FMC networks, the mobile terminal sends the detected signal levels to the control center through the WWAN or the WLAN. The control center selects one of the networks is suitable for communicating according comparing the levels of received signals with the stored thresholds. As the thresholds are fixed, the coverage of the WLAN is fixed for all mobile terminal. The switching functions from the WLAN to the WWAN are controlled by the control center. Currently, there is no way for users to adjust the coverage of the WLAN, when the users want to extend or reduce the coverage of the WLAN.
In order to solve the aforesaid problems, this invention want to provide a method and a mobile terminal to make the coverage of the WLAN can be adjustable by the mobile phone user without changing the original settings of the control center.